Is there a great white shark in UK waters?

Residents in Norfolk fear a great white shark could be in their waters after a dead porpoise was found on a beach with injuries that appear to be from a huge predator.

The 5ft-long porpoise washed up on a beach at Happisburgh with chunks of flesh torn from its mouth.

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Its injuries were consistent with it trying to fight off a larger predator.

A local who lives near to the scene told the Daily Mail: "We've heard about this latest porpoise being washed up at Happisburgh and it's not far from where the porpoises came ashore with what looked like bite marks in 2011, so of course people are worried there is something out there that's doing it."

In 2011, two porpoises washed up on Winterton Beach, near Great Yarmouth, with bite marks.

A year later, one of Britain's leading conservationists said he believes that there have been at least ten "credible" sightings of great whites in British waters in the last 18 years.

Shark conservationist Richard Peirce assessed nearly 100 reports of great whites, including a number of reports from July 1999 in a stretch of water 12 miles off north Cornwall, witnessed by eight people.

Mr Peirce wrote in BBC Wildlife Magazine: "There has been much speculation about the possible reasons for this, and one theory is that it may be due to the warming of British seas, which has led to changes in the movements of shark prey and thus shark behaviour."

He added: "I believe that there's a more straightforward explanation for the increase in reported shark encounters: it simply reflects the fact that we are spending more time at sea."